html,body
    height: 100%
    line-height: 1
    font-weight: 200
    font-family: 'PingFang SC','STHeitiSC-Light','Helvatica-Light',arial,sans-serif
    overflow: hidden

.clearfix
    display: inline-block
    &:after
        display: block
        content: "."
        height: 0
        line-height: 0
        clear: both
        visibility: hidden


@media (-webkit-min-device-pixel-ratio: 1.5),(min-device-pixel-ratio: 1.5)
    .border-1px
        &::after
            -webkit-transform: scaleY(0.7)
            transform: scaleY(0.7)
            // 这里是1.5*0.7，让它的宽度接近1
            // -webkit-min-device-pixel-ratio: 1.5
            // 是指当时显示屏最小的色倍为1.5倍的
            // 1像素的宽度运用了伪类和缩放
    .border-top-1px
        &::before
            -webkit-transform: scaleY(0.7)
            transform: scaleY(0.7)
@media (-webkit-min-device-pixel-ratio: 2),(min-device-pixel-ratio: 2)
    .border-1px
        &::after
            -webkit-transform: scaleY(0.5)
            transform: scaleY(0.5)
    .border-top-1px
        &::before
            -webkit-transform: scaleY(0.5)
            transform: scaleY(0.5)
            